1. Field of the Invention
The present invention relates generally to an apparatus for opening the rotating doors of a railway hopper car, and in particular, to a novel apparatus for either simultaneously or sequentially opening the rotating hopper car doors from a single power source.
2. Description of the Prior Art
A common type of railroad freight car in use today is the open top freight car of the type wherein the load is discharged through hoppers on the underside of the body. Such cars are generally referred to as covered hopper cars and are used to haul coal, phosphate, and other commodities.
After hopper cars are spotted over an unloading pit, the doors of the hoppers are opened, allowing the material within the hopper to be emptied into the pit. There are several methods available for opening and closing these U.S. Pat. No. 3,596,609, issued to Ortner et. al., describes a system for simultaneously opening rotating hopper doors using a longitudinally extending operating rod connected to actuating shafts extending transversely below the hopper car body Each door operating lever rotates an actuating shaft, which in turns actuates a linkage mechanism to open and close the doors.
U.S. Pat. No. 4,741,274, issued to Ferris et. al., also describes a system for operating dump doors on a railway hopper car The lever of this invention is comprised of a single plate body portion with thru pivotal connections, with the pivotal connections coplanar with the door operating struts in a substantially vertical plan passing through the vertical transverse centerline of the center sill of the car to eliminate unnecessary rotational movements of the mechanism.
Other prior art references which teach operating mechanisms for opening and closing hopper doors include: U.S. Pat. Nos. 3,187,684; 3,339,500; 3,815,514; 3,818,842; 3,872,796; 3,994,238; 4,222,334; 4,542,701; 4,601,244; 4,688,488; and 4,829,908.
There are several disadvantages to the hopper door operating mechanisms which are in use today. One problem is that the prior art mechanisms are designed such that each actuating mechanism is connected to doors from two separate hoppers. Thus, if the mechanism fails, it affects the operation of two hoppers.
Another disadvantage of the present day hopper door mechanisms is that, since the mechanisms are designed to operate doors from two adjacent hoppers, the mechanisms must push the doors closed, with compressive forces being delivered to the mechanisms. This design makes it necessary to periodically adjust the mechanism as the system wears. In addition, the compressive forces applied to the hopper doors in closing may cause buckling problems.
A further disadvantage of present day hopper cars is that current operating mechanisms limit the distance of the door motion, thus limiting the open area of the car bottom, slowing down the unloading process and causing additional costs and potential damage to the car in certain situations, such as longer periods of time in thaw sheds.